Diodes Incorporated PT8A3518BPE

Overview

PT8A3518BPE from Pericom Semiconductor is a dedicated smart electric iron controller IC with integrated shunt regulator, AC-line-synchronized timer (60Hz), 30s horizontal timeout and 15min vertical timeout, open-drain LED driver, active-high relay output, and buzzer tone generation at 4kHz. It enables automatic power cutoff in static positions for household iron safety compliance.

For engineers reviewing the PT8A3518BPE datasheet, PT8A3518BPE pinout, PT8A3518BPE application, or PT8A3518BPE equivalent, key selection criteria include AC clock frequency support (60Hz), vertical timeout duration (15min), buzzer behavior (continual tone on timeout), package type (DIP-8), and sensor interface compatibility with mechanical tilt switches.

Technical Context

The PT8A3518BPE uses AC line frequency (60Hz) as its primary timing reference via Schmitt-triggered ACCLK input, eliminating external crystal requirements. Its internal logic interprets SW pin state to distinguish horizontal (heating disabled after 30s) and vertical (heating disabled after 15min) iron orientation.

It integrates a 5V shunt regulator (VCC = 4.5–5.5V), low-power sensor signal processor with vibration immunity, and dual-output drivers: RELAY (active-high, 5mA sink) and LED (open-drain, 10mA sink). DISC/BUZ serves dual function-capacitor discharge control and 4kHz buzzer drive.

Key Specifications

Pinout & Package

DIP-8 (lead-free, JEDEC MS-001D/BA compliant) with 2.54 mm pitch; body dimensions 9.2 mm × 6.4 mm × 3.3 mm (max).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar smart iron controller applications.

Compared with PT8A3518APE, PT8A3518BPE ensures accurate 60Hz-synchronized timing in North American grids, while PT8A3516BWE offers space savings and RoHS compliance at the cost of manual soldering compatibility and thermal derating considerations.

Availability

PT8A3518BPE is available at Aetrix Electronics and suitable for household appliance safety control, electric iron manufacturing, and white-goods embedded systems requiring stable component supply across global 120V/60Hz markets.

Supply support for PT8A3518BPE includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Pericom Semiconductor (now part of Diodes Incorporated) is a fabless analog and mixed-signal IC designer focused on timing, interface, and power management solutions for consumer and industrial applications.

The PT8A351x series was developed specifically for intelligent electric iron safety control, integrating sensor interface, AC-synchronized timing, and relay/LED/buzzer drivers into a single low-cost CMOS chip.

FAQ

What is the function of the DISC/BUZ pin?

The DISC/BUZ pin serves two roles: during normal operation, it discharges an external electrolytic capacitor to stabilize and limit its voltage; when the internal timer expires, it outputs a continuous 4kHz square wave to drive a buzzer directly. It operates as an active-high output with 0.7mA source capability, eliminating the need for external driver transistors in basic implementations.

Can PT8A3518BPE operate with 240V AC input?

Yes - PT8A3518BPE itself operates from a 4.5–5.5V DC supply derived from the AC line via external rectification and filtering. The reference schematics show compatible designs for both 120V/60Hz and 240V/50Hz systems; for 240V/60Hz use, ensure the front-end resistor network (e.g., R1, R2) is recalculated to maintain proper VCC regulation and ACCLK amplitude within the Schmitt trigger's valid range.

How does the SW pin detect iron orientation?

The SW pin reads the state of a mechanical tilt sensor (e.g., mercury switch or ball switch). A logic high indicates horizontal orientation (iron lying flat), triggering the 30s timeout; a logic low indicates vertical orientation (iron standing upright), activating the 15min timeout. Internal signal processing includes hardware debounce to reject vibration-induced false triggers, ensuring reliable detection even on unstable surfaces.

Is the TEST pin required for normal operation?

No - the TEST pin is optional and inactive during standard operation. It must be pulled high (e.g., via 10kΩ to VCC) to disable test mode. When pulled low, it scales all timeouts by 0.1× (e.g., 15min → 9.6s) for rapid functional verification. Leaving it unconnected risks floating input; manufacturer recommends explicit pull-up for production units.